Alienware m17xr2 second gpu problems

Hello, Im having problems with my second gpu. I have two hd 5870 radeon cards, but I cant enable crossfire in CCC. There are no options, and when I go check the cards the in devices manager, one of them has a code 43 error. And when I check their specs with GPUZ, the second card has values that are much slower than the first one.
Also, in CCC, when I go check the hardware, I see the first card as primary adapter, and the second as linked adapter, but its lacking many values that the first one has, like the id is set to 0.
I uninstalled the first and and played skyrim using the second, it was laggy during the loading screen when it showed an item floating around so I stopped.

Im on windows 8.1 and Im also having brightness issues. I wonder if its windows8 causing all the problems as it doesnt seem to be fully supported by the m17xr2.

Thank you for you help in advance.

 

8.1 is really pushing it
i'd recommend trying windows 7 with the catalyst 13.11 beta 9.5 drivers, with ULPS disabled. A lot of what was wrote in my guide regarding crossfire 7970m's on the R2 applies to 5870m crossfire as well. Check my sig.
Although to be honest it sounds as though you either have a problem with the card or with the mobo/connector or CF cable on the card, but first you'd have to do a clean install to make sure it's not driver related.
I tried to make 7970m's CF work on Windows 8 and 8.1, and it was a total unabashed disaster. Windows 8 is still far from being a stable system.

 

Try getting back to Windows 7. If that does not work you may need to replace the cards.